Thread controller for sewing machines



Nov. 29, 1938. c. s. THOMPSON- 2,133,774

jTHREAD CONTROLLER FOR SEWING MACHINES Filed June 1, 1935 5 Sheets-Sheet 1 WITNESSES:

INVENTOR: Larlas 5 Thompson f I BYWIZASJ. 7720721 25022,

Nov. 29, 1938. c. s. THOMPSON 2, 3

THREAD CONTROLLER FOR SEWING MACHINES Filed June 1, 1955 3 Sheets-Sheet 2 "I!" u U I? WI TNESSES: INVENTOR:

Nov. 29, 1938. c. s. THOMPSON THREAD CONTROLLER FOR SEWING MACHINES I Filed June 1, 1935 3 Sheets-Sheet 5 INVENTOR:

. WITNESSES:

Charles S. Thom 275072;, BY I I TTORINEYS. g

Patented Nov. 29, 1938 UNiTED STATES PATENT OFFICE THREAD FOR SEWING HINES 'Application June 1,1935, Serial No. 24,495

2 Claims.

This invention relates to thread controllers more particularly adapted for use in connection with sewing machines to control the threads incident to formation of seams by co-operating seaming needles and thread-carrying loopers.

The aim of my invention is to make it possible to smoothly and compensatively take up the slack occasioned in the threads by the movements of the loopers, so that tight stitches are produced without imposition of strains likely to cause breakage of the threads when the sewing machines are operated at high speeds.

The foregoing object I realize in practice, through provision of a simple thread take-up l5 wherein a rotary thread-contacting single disk controller cam on a shaft from which the looper of the sewing machine derives its motion, projects through a slot in an oil splash guard plate overlying said shaft; and wherein a thread-detaining 20 member operates to confine the threads to lateral movement along the surface of the guard plate under the action of the controller cam, while stationary self -threading hooked guides having elongate throats in parallelism with the slot at oppo- 25 site sides thereof, cooperate to direct the thread crosswise of said slot as well as to limit the extent of lateral movement of the thread when the controller cam rotates in the normal direction.

Other objects and attendant advantages of this 30 invention will appear from the detailed description following of the drawings, wherein Fig. I is a fragmentary plan view of the base portion of a sewing machine embodying my new thread controller, a portion of the work plate of the 35 machine having been broken away to expose the mechanism beneath.

Fig. II is a fragmentary cross sectional view, taken as indicated by the arows IIII in Fig. I. Fig. 111 is a perspective view of the guard plate 40 of the thread controller together with the attached thread detaining member and the thread guides. I

- Fig. IV is a fragmentary view corresponding to Fig. 1, showing an alternative form of my inven- 45 tion.

Fig. V is a fragmentary sectional view,' taken as indicated by the arrows V-V in Fig. IV; and Fig. is a perspectiveview of the guard plate embodied in the alternative form of my inven- 50 tion featured in Figs. 1V and V.

The sewing machine chosen for convenience of illustration-herein is, generally speaking, of wellknown construction, and, as shown, comprises a bed l'- with spaced upstanding bearing pedestals I 55 2 and 3 for a longitudinally extending drive shaft 4. The work plate 5 of the machine is suitably secured to the tops of the pedestals 2 and 3 at an elevation above the bed, and provided with a removable inset throat plate I having an aperture 8 for passage of the vertically-reciprocat- 5 ing seaming needle 9, as well as a clearance opening It for the feed dog it wherewith a presser foot I2 cooperates. Below the throat plate I is a looper E3 on a carrier l4 mounted for swinging movement crosswise of the needle 9 about a 10 stud l5 which projects from an oscillating arm l6 'afiixed to a longitudinal rock shaft ll. As

shown, this rock shaft ll is journaled in the hearing pedestals 2 and 3 to one side of the main'shaft 4. The looper carrier I3 is oscillated through a horizontal link 18, by an arm IS on a transverse shaft which is journaled in bearings also afforded by the bed i, and which is rocked through suitable means not illustrated, from said main shaft 4. The longitudinal rock shaft I1 20 is in turn actuated by an arm 2| connected with an eccentric 22 on the main shaft 4. Due to the connections just described, the looper i3 is operated in the well-known way to interloop its thread T with the needle thread T incident to the formation of fabric seams by the machine. The feed dog bar 23 is reciprocated horizontally by means of a rocker 25 whereto it is pivotally connected at 26, the shaft 21 of said rocker being disposed in parallelism with the main shaft 4 at the side opposite the rock shaft 11, and journaled in spaced bearing lugs 28 and 29 of the bed plate I. The rocker 25 is oscillated through the medium of horizontal and vertical links 30 and 3|, from a crank disk 32 on the main shaft .4; and

another eccentric 33 on the main shaft having a pivotal connection with a curved pendant arm 34 of the feed bar 23, is relied upon to impart up and down movements to the feed dog II as required. a

The thread controller means with which the present invention is more particularly concerned includes a single disk rotary thread-engaging cam 35, which, as shown in Fig. I, is secured to the shaft 4 in the interval between the bearing pedestal 3 and the eccentric 22. Rigidly attached to the pedestal 3 by a screw 36 is a guard plate 31 with an upwardly sloping portion 38 which overreaches the main shaft 4, and which has a slot 39 through which the cam disk 35 projects. As shown in Figs. I and III, the guard plate 31 has a longitudinal slot through which the shank of the securing screw 36 passes, so that said plate can be adjusted laterally of the cam 35 and its slot 39 thereby properly centered in respect to the cam. Mounted on the guard plate 3? is a thread retaining tongue 55 which, in this instance, is fashioned to U-configuration from stout wire. As shown, the tongue All is of a length to extend beyond the periphery of the thread controller cam 35, and closely surrounds the slot 39. The side portions or bars ll of the retaining tongue 60 extending along the edges of the slot 39 at opposite sides of the plane of the cam 35, terminate in outwardly-turned loops 12 that receive the securing screws 43. From Fig. II it will be observed that the tongue 4t is slightly elevated from the upper face of the guard plate 31 substantially throughout its length, with resultant provision of narrow intervals 44 between its side bars ll and said guard plate for passage of the looper thread T. At opposite sides of the thread retaining tongue 40 are thread guides 45 which, like said tongue, are fashioned from wire with loops 46 for the securing screws 43, and with hooks 41 whereof the throats constitute elongate thread eyes in parallelism with the slot. The screws 43 thus constitute means whereby the thread guides 45 can be adjusted relative to the retaining tongue 40.

The looper thread T is supplied from a spool (not shown), and directed through a guide flii at the front of the machine near the right-hand end of Fig. I below the work plate 5. From the guide 48 the thread T' passes forwardly and inwardly at an angle, to the right-hand hook guide 45 on the guard plate 31, then beneath the detaining tongue 40 and across the slot 39 in said plate, to the other book eye 45, and from thence to the looper l3. As the rotary thread controller cam 35 revolves, its high peripheral portions whip up through the slot 39 in the guard plate 31 and deflect the thread T upward in the interval between the laterally spaced side bars 4! of the detaining tongue 40, thereby taking up the slack of the said thread at the proper times during the loop forming cycle. With the cam disk 35 rotating normally in the direction of the arrow in Fig. II, definite control of the thread T is had through the detaining or holding down action of the bars 41 of the tongue 40 on theone hand, and the restraining action of the hook eyes 45 upon the thread against lateral movement along the surface of the guard plate 31 in the direction of cam rotation. In this connection it is to be particularly noted that the length of the detaining tongue is such as to insure retainment of the thread by the hook eyes 45 in the event that the machine is reversely driven and the thread T carried laterally upward of the guard plate under the reverse rotation of the thread cam 35.

In threading the machine, the looper thread T is passed through the guide 48, then drawn inward laterally and allowed to enter into the open ends of the hook eyes 45 on the guard plate 31 from above, and then threaded through the eyes of the looper l3. With this accomplished, the thread T is grasped between the hook eyes 45, drawn downward, and finally slipped under detaining tongue 40 on the guard plate 31. Due to the rounding of the free end of the detaining tongue 40 and the upward bending of the hook ends 41 as shown, threading in the above manner arsarva is obviously made easy so that it can be eflecte in a minimum of time.

In addition to serving as a means for supporting the thread detaining member Ml and the guide eyes $5, the guard plate 37! acts as a shield to prevent splash of oil upon the looper thread T from the rotary cam 35 and contiguous parts on the shaft ii, and it furthermore prevents said thread from becoming caught and wrapped about said cam and shaft in case of breakage. If found desirable, the guard plate ea may be widened so as to extend over the eccentric 22 and thereby prevent oil splash upon the looper thread T from that source.

In the alternative embodiment of my inven= tion shown in Figs. IV-VI, the guard plate 31a is rounded to overreach the shaft iand provided with a foot portion 58 for attachment to the bed i of the machine by a pair of screws 35a. The slot 391; in the guard plate 37a, through which the rotary thread controller cami'35 projects, is in this case open at one end. Adjacent the open end of the slot 39a, the guard plate 37a is formed with laterally-bent ears 49 which are fitted with porcelain thread eyes 5511, the

centers of said eyes being aligned transversely of the slot in close proximity to the outer'surface of said plate as shown. The detaining tongue of the first described embodiment is dispensed with here since the eyes 55a serve both as guides and as means for restraining the thread T against lateral displacement. In all other respects the modification featured in Figs. IV--VI functions exactly as described in connection with the first described embodiment of my invention; and, in order to dispense with the necessity for repetitive description, the same reference numerals have been employed to indicate the interrelated parts of the sewing machines.

Having thus described my invention, I claim: 1. A thread controller. comprising a rotary shaft; a thread controlling cam on said shaft; a guard plate parallel with the shaft and having a slot through which the cam projects; guides at opposite sides of the slot for limiting the play of the thread; means for securing the guides to the guard plate; and a detaining element cooperative with the guides in holding the thread in a plane parallel to the guard plate, said element being fastened to said guard plate by the same securing means.

2. A thread controller comprising a rotary shaft; a thread controlling cam on said shaft;

a guide plate parallel with the shaft and having a slot through which the cam projects; guides at opposite sides of the slot for limiting the play of the thread,said guides being in the form of elongated hooks open at one end and having anchorageeyes; headed securing screws passing through the eyes of the guides into the guard plate; and a detaining element cooperative with the guides in holding the thread in a plane parallel to the guard plate, said element being also open at one end and formed at the other end with anchorage eyes for attachment to said guard plate by the same securing screws.

CHARLES s. rr-iowson. 

